Where have all the towers gone? asks Mike Short, Vice President at Telefónica and veteran Mobile World Congress attendee. Over more than 20 years, he tells Ian Scales, he's seen the event become more 'digital' world congress as the industry has matured and, above all, grown. With more than 7 billion customers the industry is now about trying to sell more services, not just to people but to machines. He's looking forward to it.